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Re: Debugging "No Smoking" sign boot failures
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Re: Debugging "No Smoking" sign boot failures

Dave --

When a Mac boots up, and you get the "No Smoking" (circle with a slash through it), what exactly does that mean?

The exact reason is that the boot timeout has expired (i.e. your root device was not discovered within the alloted time by the kernel - 60 seconds IIRC).

A client of mine has been seeing occasional booting failures if their software is installed.  It is a boot time kext with OSBundleRequired set to Root.  Is it possible for a kext to cause this kind of boot failure?  I figured that error was coming from EFI before the kernel even started to boot.

This image is not drawn by EFI. It is drawn by the kernel. If a boot time kext is installed and prevents the root device from being found, that could cause this.

Also, any suggestions on how to debug the issue?  If I enable verbose boot, it all boots fine.

Do you ever see a timeout in the verbose boot ("Still waiting for root device....")? That is the verbose equivalent.

FWIW, this problem seems to be hardware specific, meaning they have a bunch of machines (allegedly these are the same hardware and OS).  The problem always seems to manifest itself on the same machines, i.e. there are some machines that never exhibit the problem.

There are a few boot-args you can set which will dump the IORegistry in the verbose output to see what the state of the registry is and if the root device stack has not fully built up. Search "IOKitDebug.h" for the various options that get checked in xnu/iokit/bsddev/IOKitBSDInit.cpp.

If ethernet has come up and the debugger is available, you can also attach to the machine and see what's preventing the root device from showing up (you can dump the registry information in the debugger and you can inspect all the kernel stacks to see where one might be blocked/deadlocked).

HTH,

-- Chris


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 >Debugging "No Smoking" sign boot failures (From: Dave Dribin <email@hidden>)



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